mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-09-07 21:33:24 +09:00
![Heinrich Schuchardt](/assets/img/avatar_default.png)
Use syntax highlighting for a Linux console session. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
85 lines
2.6 KiB
ReStructuredText
85 lines
2.6 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0+
|
|
|
|
PStore command
|
|
==============
|
|
|
|
Design
|
|
------
|
|
|
|
Linux PStore and Ramoops modules (Linux config options PSTORE and PSTORE_RAM)
|
|
allow to use memory to pass data from the dying breath of a crashing kernel to
|
|
its successor. This command allows to read those records from U-Boot command
|
|
line.
|
|
|
|
Ramoops is an oops/panic logger that writes its logs to RAM before the system
|
|
crashes. It works by logging oopses and panics in a circular buffer. Ramoops
|
|
needs a system with persistent RAM so that the content of that area can survive
|
|
after a restart.
|
|
|
|
Ramoops uses a predefined memory area to store the dump.
|
|
|
|
Ramoops parameters can be passed as kernel parameters or through Device Tree,
|
|
i.e.::
|
|
|
|
ramoops.mem_address=0x30000000 ramoops.mem_size=0x100000 ramoops.record_size=0x2000 ramoops.console_size=0x2000 memmap=0x100000$0x30000000
|
|
|
|
The same values should be set in U-Boot to be able to retrieve the records.
|
|
This values can be set at build time in U-Boot configuration file, or at runtime.
|
|
U-Boot automatically patches the Device Tree to pass the Ramoops parameters to
|
|
the kernel.
|
|
|
|
The PStore configuration parameters are:
|
|
|
|
======================= ==========
|
|
Name Default
|
|
======================= ==========
|
|
CMD_PSTORE_MEM_ADDR
|
|
CMD_PSTORE_MEM_SIZE 0x10000
|
|
CMD_PSTORE_RECORD_SIZE 0x1000
|
|
CMD_PSTORE_CONSOLE_SIZE 0x1000
|
|
CMD_PSTORE_FTRACE_SIZE 0x1000
|
|
CMD_PSTORE_PMSG_SIZE 0x1000
|
|
CMD_PSTORE_ECC_SIZE 0
|
|
======================= ==========
|
|
|
|
Records sizes should be a power of 2.
|
|
The memory size and the record/console size must be non-zero.
|
|
|
|
Multiple 'dump' records can be stored in the memory reserved for PStore.
|
|
The memory size has to be larger than the sum of the record sizes, i.e.::
|
|
|
|
MEM_SIZE >= RECORD_SIZE * n + CONSOLE_SIZE + FTRACE_SIZE + PMSG_SIZE
|
|
|
|
Usage
|
|
-----
|
|
|
|
Generate kernel crash
|
|
~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
For test purpose, you can generate a kernel crash by setting reboot timeout to
|
|
10 seconds and trigger a panic
|
|
|
|
.. code-block:: console
|
|
|
|
$ sudo sh -c "echo 1 > /proc/sys/kernel/sysrq"
|
|
$ sudo sh -c "echo 10 > /proc/sys/kernel/panic"
|
|
$ sudo sh -c "echo c > /proc/sysrq-trigger"
|
|
|
|
Retrieve logs in U-Boot
|
|
~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
First of all, unless PStore parameters as been set during U-Boot configuration
|
|
and match kernel ramoops parameters, it needs to be set using 'pstore set', e.g.::
|
|
|
|
=> pstore set 0x30000000 0x100000 0x2000 0x2000
|
|
|
|
Then all available dumps can be displayed
|
|
using::
|
|
|
|
=> pstore display
|
|
|
|
Or saved to an existing directory in an Ext2 or Ext4 partition, e.g. on root
|
|
directory of 1st partition of the 2nd MMC::
|
|
|
|
=> pstore save mmc 1:1 /
|